In many industrial applications, robots are used for storage and retrieval of items. In warehouses and foundries, shelving racks are constructed for storage of items. The shelving racks typically have multiple vertical levels on which items are stored on pallets. The robots, which move both vertically and horizontally between the shelving racks, place the pallets in the shelving racks and also pick up and carry the pallets away from the shelving racks.
In sand casting foundries, shelving racks may be used to store pallets. The pallets may hold molds, which may be empty or filled. The pallets may be transported and placed in a pouring area where molten metal is poured into the mold to form metal parts. Because the pouring area is generally located at a distance from the storage area, robots, conveyors and ram drives are needed to move the pallets from the storage area to the pouring area.
A typical storage and retrieval system in a foundry may have two input slots and two output slots. An empty mold is placed into the first input slot. A robot may pick up the empty mold from the first input slot and carry and place the mold in a shelving rack. Later, the robot may retrieve the empty mold and carry and place the mold in the first output slot. A conveyor may then move the empty mold to a pushing station. At the pushing station, a ram drive forces the mold across a pouring table. The process is continued until a predetermined number of empty molds are lined up on the pouring table. Since the pouring area is typically located away from the shelving racks, powered conveyors and ram drives are needed to move the pallet to the pouring area.
At the pouring area, a crucible of molten metal is moved into place over the empty molds and tipped over to pour the molten metal into the empty molds. After the molds are filled with the molten metal, the filled molds, each weighing approximately 4000 lbs., are left for a predetermined time period for a “skin” to form at the boundary between the mold and the metal. Once the filled molds can be safely moved, the ram drive slowly pushes the filled molds back onto a second conveyor, which moves the filled molds to the second input slot. The robot then picks up and carries the filled molds to the shelving rack or to a separate resting slot. The filled molds are allowed to rest for a predetermined time period to allow the molds to cool. Thereafter, the robot carries the filled molds to the second output slot. The filled molds are then moved to a shaker where metal parts are separated from the molds.
Thus, it will be apparent that conventional systems are complex and inefficient because they require conveyors and a ram drive. Also, conventional systems require a large area because the conveyors and the ram drive must be installed. Accordingly, improved systems and methods are needed.